stable points
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2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Promode R. Bandyopadhyay

AbstractOrigin of scale coupling may be clarified by the understanding of multistability, or shifts between stable points via unstable equilibrium points due to a stimulus. When placed on a glasstop hotplate, cobs of corn underwent multistable autonomous oscillation, with unsteady viscous lubrication below and transitional plumes above, where the buoyancy to inertia force ratio is close to ≥ 1.0. Subsequently, viscous wall-frictional multistability occurred in six more types of smooth fruit with nominal symmetry. Autonomous motion observed are: cobs roll, pitch and yaw; but green chillies, blueberries, tropical berries, red grapes, oblong grapes and grape tomatoes roll and yaw. The cross products of the orthogonal angular momentum produce the observed motion. The prevalence of roll and yaw motion are the most common. Lubricant film thickness h$$\propto$$ ∝ U/(TF), for cob mass F, tangential velocity U and temperature T. In heavier cobs, the film thins, breaking frequently, changing stability. Lighter cobs have high h, favoring positive feedback and more spinning: more T rises, more viscosity of water drops, increasing U and h more, until cooling onsets. Infrequent popping of the tender corn kernel has the same mean sound pressure level as in hard popcorn. The plume vortex jets lock-in to the autonomous rolling cob oscillation. Away from any solid surface, the hot-cold side boundary produces plumes slanted at ± 45°. Surface fencing (13–26 μm high) appears to control motion drift.


2021 ◽  
pp. 37-52
Author(s):  
Heather Lovell

AbstractNodes within smart grids play an important role in providing stability—keeping things the same—as well as innovating. The theme of nodes is closely related to that of networks, as nodes are fixed, stable points on networks. But whereas the network metaphor encourages us to think about connections and flows, the concept of nodes focuses our attention on the key organisations, people, and technologies that provide stable anchor points and typically act as brokers at crucial intersections within the energy sector. In this chapter, I examine social and technical nodes using three examples: the digital electricity meter, with a focus on household transitions in the UK and Australia, an energy authority (the Australian Energy Market Operator), and islands, specifically looking at the smart grid on King Island, Australia.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Majed G. Alharbi ◽  
Hamiden Abd El- Wahed Khalifa

The Delphi method is a process where subjective data are transformed into quasi-objective data using statistical analysis and are converged to stable points. The Delphi method was developed by the RAND Corporation at Santa Monica, California, and is widely used for long-range forecasting in management science. It is a method by which the subjective data of experts are made to converge using some statistical analyses. This article proposes a variation of the Delphi method using triangular fuzzy numbers, where the communication method with the experts is the same, but the estimation procedure is different. The utility of the method is illustrated by a numerical example.


Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Li Ma ◽  
Yidi Wang ◽  
Yun Teng

PurposeChina's agricultural production trusteeship is characterized by the organic link between household operation of small-scale peasant economy and agricultural socialized services, which releases agricultural development vitality and promotes agricultural modernization. As one of the agricultural production trusteeship modes, the whole process trusteeship is suitable for the actual situation of China's aging population and labor force transfer. This paper aims to construct an evolutionary game model containing multistakeholder to explore the behavior decisions through numerical simulation and to provide useful suggestions for the formation of a positive and stable trusteeship relationship and the sound development of the whole process trusteeship of agricultural production.Design/methodology/approachThe paper incorporates village committees, service organizations and farmers into the same research framework, selects “guarantee + dividends” as the income distribution method and applies the evolutionary game method to analyze behavioral choices and evolutionary paths of stakeholders. By constructing the expectation function, establishing the replicator dynamic equations and analyzing the tripartite evolutionary stability strategy, the authors explore the factors that affect the stakeholders’ strategy choice and determine asymptotically stable points and stability conditions.Findings(1) There is a game relationship among village committees, farmers and service organizations in the whole process trusteeship of agricultural production, asymptotically stable points (0,0,1) and (1,1,1) are obtained through calculation. (2) The proportion of stakeholders' strategy choice, the weight of the whole process trusteeship of agricultural production in the performance appraisal of the village committee, the village committee's supervision cost, the village committee's reputation effect and the penalty for false dividends of the service organization will affect the speed at which the curve representing the tripartite relationship approaches two asymptotically stable points.Research limitations/implicationsThe countermeasures proposed in the paper have excellent reference value. (1) For areas that have realized the project: Village committees can solve the trusteeship problems exposed in the initial areas and improve farmers' satisfaction with the project. (2) For areas that have not realized the project: Those regions will receive more experience references and enhance their confidence in this project. The limitation of the paper is that it takes the main grain-producing areas in only the three northeastern provinces of China as the research object. The next research object will be extended to the whole country.Practical implicationsThis paper propose strategies for realizing the orderly operation of the whole process trusteeship of agricultural production: first, increase the proportion of stakeholders' strategy choices; second, reduce the village committee's supervision cost; third, increase the weight of the whole process trusteeship of agricultural production in the performance appraisal of the village committee; fourth, improve the village committee's reputation effect; fifth, increase the penalty for false dividends of the service organization.Originality/valueAgricultural production trusteeship is in its initial stage in China. The interest relationships between stakeholders are not yet clear. The paper innovatively applies the evolutionary game method to the research field of the whole process trusteeship of agricultural production. According to conditions in China, based on ensuring the guaranteed income, the paper introduces the dividend income variable and establishes a tripartite game model of village committees, service organization and farmers. The paper provides suggestions for the orderly and healthy development of China's agricultural production trusteeship and provides experience for the operation of other modes of agricultural production trusteeship.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhuo Wang ◽  
Zixuan Wang ◽  
Likai Wang

The importance of automatic pollen recognition has been examined in several areas ranging from paleoclimate studies to some daily practice such as pollen hypersensitivity forecasting. This paper attempts to present an automatic 3D pollen image recognition method based on convolutional neural network. To achieve this purpose, high feature dimensions and complex posture transformation should be taken into account. Therefore, this work focuses on a three-part novel approach: constructing spatial local key points to obtain local stable points of pollen images, computing orientational local binary pattern using local stable points as the inputs, and identifying the pollen grains using convolutional neural network as the classifier. Experiments are performed on two standard pollen image datasets: Confocal-E dataset and Pollenmonitor dataset. It is concluded that the proposed approach can effectively extract the features of pollen images and is robust to posture transformation, slight occlusion, and pollution.


Author(s):  
M.A. Kovalevskaya ◽  
◽  
O.A. Pererva ◽  

Vitreomacular interface is an important part of the diagnosis from retinopathy of prematurity (ROP) to retinal diseases in adults. It is required to develop a method for macula localization to determine 3 stable points for photographic measurements of a 3D eye model. Purpose. To minimize the risk of mistakes in the diagnosis and choice of treatment for ROP and diabetic angioretinopathy (DARP) by improving the quality and analysis of modeled wide-field images on the Key to Diagnosis I and II platforms. Material and methods. 1278 RetCam and fundus images of 402 patients. 3 clinical groups: 1 – ROP 272 (544 eyes): 1A – I stage 152(304 eyes), 1B – II stage 45 (90 eyes), 1C – III stage 8 (12 eyes), 1D – posterior aggressive ROP 7 (14 eyes), 1E-retinal immaturity 60 (120 eyes); 2 – DARP 120 (240 eyes): 2A – non-proliferative 13 (17 eyes), 2B – preproliferative 47 (55 eyes), 2C – proliferative 27 (33 eyes), 2D – terminal 33 (37 eyes), 3 – control 10 (20 eyes). A standard clinical examination, analysis of modeled wide-field images, localization of the macula and traction index of the macular region (Tm) were performed. Results. Platform modules have been developed for automatic wide-field images modeling and macular localization, which is a reference point for assessing the extent of pathological changes. In ROP there was significant negative correlation of the Tm value with a stage: 1А – 0,8±0,03, 1B – 0,75±0,04, 1C – 0,74±0,13, 1D – 0,99±0,01, 1E – 0,91±0,09. For groups 2A – 2B, there was no correlation between Tm and the DARP severity. Conclusion. Tm reflects the severity of traction processes at the periphery of the retina and can be used as a marker in case of diagnostic defects in ROP. The localization of the macula determines the stable points for automatic morphometry. Key words: retinopathy of prematurity, pediatric retinal camera RetCam-Shuttle, telemedicine, diabetic angioretinopathy, vitreomacular interface.


2021 ◽  
Author(s):  
Zhiyong Dai ◽  
Guangqi Li ◽  
Mingdi Fan

This paper analyzes the global stability of synchronous reference frame phase-locked loops (SRF-PLLs), from a large signal viewpoint. First, a large signal model of SRF-PLL is accurately established, without applying any linearization method. Then, According to the phase portrait tool, the global stability of SRF-PLL is discussed in the nonlinear frame. Compared with existing methods, the proposed analysis, not relying on small signal model and linearization method, provides a global discussion of SRF-PLL stability. Some novel discoveries are as follow: 1) SRF-PLL has infinite equilibrium points, including stable points and saddle points; 2) Although saddle points are unstable in local regions, there still exists two special lines for each saddle point, and SRF-PLL converges to a certain saddle point when the initial states are on its special lines. 3) These special lines of saddle points divide the global region of SRF-PLL into infinite small regions. A Lyapunov-based discussion proves that SRF-PLL converges to different stable points, when the initial states are in the different small regions. The experiment results have been verified the global stability analysis of SRF-PLL.


2021 ◽  
Author(s):  
Zhiyong Dai ◽  
Guangqi Li ◽  
Mingdi Fan

This paper analyzes the global stability of synchronous reference frame phase-locked loops (SRF-PLLs), from a large signal viewpoint. First, a large signal model of SRF-PLL is accurately established, without applying any linearization method. Then, According to the phase portrait tool, the global stability of SRF-PLL is discussed in the nonlinear frame. Compared with existing methods, the proposed analysis, not relying on small signal model and linearization method, provides a global discussion of SRF-PLL stability. Some novel discoveries are as follow: 1) SRF-PLL has infinite equilibrium points, including stable points and saddle points; 2) Although saddle points are unstable in local regions, there still exists two special lines for each saddle point, and SRF-PLL converges to a certain saddle point when the initial states are on its special lines. 3) These special lines of saddle points divide the global region of SRF-PLL into infinite small regions. A Lyapunov-based discussion proves that SRF-PLL converges to different stable points, when the initial states are in the different small regions. The experiment results have been verified the global stability analysis of SRF-PLL.


2021 ◽  
Author(s):  
Mei Guo ◽  
Ran Yang ◽  
Meng Zhang ◽  
Renyuan Liu ◽  
Yongliang Zhu ◽  
...  

Abstract In this paper, a novel memcapacitor is designed by SBT memristor and two capacitors. A fifth-order memcapacitor and memristor chaotic circuit is proposed. The stability of the equilibrium point of the system is analyzed theoretically. Lyapunov exponents spectra, bifurcation diagrams, poincaré maps and phase diagrams are used to analyze the dynamic behaviors of the system. The results show that under different initial values and parameters, the system produces rich dynamic behaviors such as stable points, limit cycles, chaos, and so on. Specially, coexisting attractors, transient chaos, and steady-state chaos accompanied by burst period phenomenon are also produced in the system. The proposed memcapacitor-based circuit expands the research methods of memcapacitor for application in chaoticcircuits.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1739
Author(s):  
Waldemar Odziemczyk

Geodetic measurements are commonly used in displacement analysis to determine the absolute values of displacements of points of interest. In order to properly determine the displacement values, it is necessary to correctly identify a subgroup of mutually stable points constituting a reference system. The complexity of this task depends on the spatial size of the network, the timespan of measurements and geological conditions affecting the type of changes in the location of points. As a consequence of the abovementioned factors, the task of stable identification in a longer timespan for a subgroup of points may produce equivocal results. In particular, it is likely that alternative subgroups of reference points meeting the mutual stability criteria will be selected, sometimes without common reference points. The proposed method of reference system identification utilises optimisation algorithms. Two such algorithms were tested, i.e., simulated annealing (SA) and Hooke-Jeeves (HJ) method. Two numerical examples were used to test the proposed method. Although in the first example both methods delivered a positive result, the second example showed the superiority of the SA method over the HJ. The proposed method can be considered a tool supporting the person analysing and making calculations in reaching the ultimate decision on reference points.


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